Laboratory grade distilled water was used for all activity. This was obtained by distilling water from a still of allborosilicate
glass, fused quartz, tin, or titanium. Distillation from an acid solution was introduced to remove
ammonia. CO2 was removed by boiling the water for 15 minutes and cooling rapidly to room temperature, while
atmospheric CO2 was excluded by using a tube containing soda lime or a commercially available CO2 removing
agent. Since boiling the water may add other impurities by leaching impurities from the container, fresh filters
regularly replaced old ones. Cartridges and resins initially can release impurities as well. Pretreatment on reagent
water was carried out where water contains significant concentrations of calcium, magnesium, and bicarbonate ions.
When required, demineralization via reverse osmosis or ion exchange was also introduced.